The overall aim of this project is the understanding of the electronic structures of the constituents of reaction centers in the photosynthetic apparatus of bacterial systems and chloroplasts with emphasis on the former. In the past nine months, we have concentrated mainly on the understanding of the electronic structures and hyperfine properties of the monomer unit of the electron donor systems in the reaction centers of bacterio-chlorophyll (and the related bacteriopheophytin monomer) and chlorophyll systems, although we have also recently started work on the acceptor molecules in the reaction centers of bacterial photosynthetic systems. Our efforts for the next year will be channeled in four main directions, (a) the continuation of the study of magnetic and quadrupole hyperfine interactions in monomer systems of bacteriopheophytin, bacteriochlorophyll, pheophytin and chlorophyll, both the free radicals (cations and anions) and the neutral molecules, (b) the properties of the triplet monomer states such as the zero-field spin-Hamiltonian parameters D and E as well as the triplet-singlet crossing parameters ki responsible for the spin-polarization in triplet states, (c) the understanding of the nature of electron sharing between the two monomer units of the dimer "special pair" which is considered to represent the donor in the reaction centers of bacterial photosynthetic systems and (d) the electronic structures and hyperfine properties of the reduced acceptor systems with the Fe ion 2 removed, and also the interaction between Fe ion 2 and acceptor molecules.